Yes, an urgent cervical spine MRI should be ordered immediately for this patient.
This patient has classic upper motor neuron signs indicating cervical spinal cord compression (myelopathy), which constitutes a neurological "red flag" requiring urgent imaging regardless of the absence of pain or sensory symptoms.
Clinical Reasoning
Your patient presents with a constellation of findings that are highly specific for cervical myelopathy:
- Bilateral brisk deep tendon reflexes (hyperreflexia)
- Bilateral positive Hoffmann's signs
- Bilateral positive pectoralis signs
Why These Findings Demand Urgent Action
The bilateral pectoralis reflex is particularly significant 1. Research demonstrates that a hyperactive pectoralis jerk is specific for upper cervical spinal cord compression at C2-3 and/or C3-4 levels (p < 0.004). In a study of 15 patients with cervical myelopathy, no patient with compression at or below C4-5 without higher-level involvement had hyperactive pectoralis reflexes 1.
The bilateral Hoffmann's sign further strengthens this concern 2. When present bilaterally, this sign demonstrates 91% correlation with spinal cord compression on MRI, compared to only 50% when unilateral 2. In patients with surgically-treated cervical myelopathy, the Hoffmann sign appears in 68% of cases and is more prevalent in patients with less severe neurological deficits (46% in mild myelopathy with mJOA scores 14-16) 2.
The Guideline Framework
While the ACR Appropriateness Criteria 3 state that MRI is not useful as first-line imaging "in the absence of red flag symptoms," your patient clearly has red flag symptoms—these are objective upper motor neuron signs indicating spinal cord compromise. The guidelines specifically reference the need for imaging when neurological symptoms are present.
MRI cervical spine without IV contrast is the most sensitive imaging modality for assessment of soft tissue abnormalities and spinal cord compression 3. Contrast is not necessary unless there is concern for infection, tumor, or inflammatory processes.
Critical Pitfalls to Avoid
The "Asymptomatic" Trap
Do not be misled by the absence of pain, tingling, or numbness. Cervical myelopathy can present with pure motor findings without sensory complaints 4. A case report describes a 67-year-old initially attributed to carpal tunnel syndrome who had trouble ambulating, rhythmic ankle clonus, and bilateral Hoffmann's sign—ultimately requiring emergent spinal cord decompression 4.
The Cognitive Symptom Connection
The provider's focus on cognitive impairment and fatigue as autoimmune encephalitis may have created diagnostic anchoring bias. Cervical myelopathy can cause gait instability and functional decline that might be misattributed to central processes. The negative workup for autoimmune encephalitis (normal brain MRI, CSF, EEG) should prompt reconsideration of the cervical spine as the source.
Dynamic Examination Findings
Research shows that 41% of patients with cervical stenosis have dynamic changes in reflex examination with neck positioning 5. The most common dynamic change is in the Hoffmann's reflex (28% of patients). If reflexes were not tested in multiple neck positions (neutral, flexed, extended), the examination may have underestimated the severity.
Urgency Considerations
This should be considered urgent, not routine imaging, for several reasons:
- Bilateral upper motor neuron signs indicate bilateral cord involvement
- Progressive myelopathy can lead to irreversible spinal cord damage
- Early surgical decompression in symptomatic cervical myelopathy improves outcomes
- The combination of bilateral Hoffmann's and pectoralis signs suggests upper cervical involvement (C2-4 level), which can progress to respiratory compromise if severe
Practical Next Steps
- Order MRI cervical spine without contrast urgently (within 24-48 hours, not weeks)
- Document the specific upper motor neuron findings in the order to justify urgency
- Consider neurosurgical consultation if MRI confirms significant cord compression
- Advise the patient to avoid neck hyperextension until imaging is complete, as this can worsen cord compression 5
The absence of pain does not indicate absence of serious pathology—in fact, painless myelopathy can be more insidious and progress further before detection.